Adjust the network shown below by the method of least squares. $(10$ pts$.)$

The coordinates $(m)$ for control stations are:

$A$:$x=4356\mathrm{.}78$

$y=2340\mathrm{.}97$

B: $x=4359\mathrm{.}83$

$y=3981\mathrm{.}00$

a$)$ What is the reference standard deviation, $S_0?$

b$)$ List the adjusted coordinates of the unknown stations and their standard deviations.

c$)$ Tabulate the adjusted observations, their residuals and their standard deviations.

d$)$ Compare your results with the ones which you obtained in the Assignment$-6$ and

comment on them.